The Supreme Court this week made tougher regulation of greenhouse gases inevitable in America. It won't be immediate, and the Bush administration will continue to try to wriggle out of its obligations.

But in a 5-4 vote, the court declared firmly that the Clean Air Act gives the Environmental Protection Agency a duty to control auto emissions.

The decision was a victory for environmentalists and a rebuke to the Bush administration, which stubbornly had maintained that it had no right to control carbon dioxide and other gases under the Clean Air Act, and that even if it did, it would not do so.

Scientific evidence is overwhelming that the Earth is warming. Despite a few die-hard doubters, the clear consensus among climate scientists is that human activity is a significant reason for the warm-up, the effects of which could be severe and costly. The Bush administration stubbornly has refused to regulate greenhouse gases, claiming that government lacked the authority and that regulation is not needed. The administration asserted, incredibly, that carbon dioxide and other greenhouse gases are not pollutants under the Clean Air Act. The court disagreed, finding that government has a legal responsibility to regulate any pollutant that affects public health or welfare, including effects on weather and climate.

According to the court, government can avoid taking action only if it determines that greenhouse gases don't cause climate change - which demonstrably is false - or that government can't determine if they do or don't. That dodge, to which members of the Flat Earth Society have clung, no longer will work.

The question now is: How long it will take the government to apply reasonable controls? The case applies specifically to tailpipe pollution, but the trend in the Democratic Congress and in public opinion clearly is moving toward tougher regulation of pollutants.

American business has started to line up with the greens. In January, 10 of the nation's biggest companies, including Caterpillar, Alcoa, DuPont and General Electric, called on President George W. Bush to limit greenhouse gases and fund more research into renewable industry.

Even the electrical power industry is resigned to tighter carbon dioxide controls. That, plus a federal tax break, explains the power companies' new interest in building nuclear power plants after a 29-year hiatus. Nuclear plants emit virtually no greenhouse gases, although the disposal of their radioactive waste remains a volatile subject of public debate and anxiety in the United States.

Business deserves a seat at the table as controls are negotiated. Done smartly, and phased in gradually, greenhouse gas reductions should cause little damage to the economy.

Emissions from autos and power plants may be the easiest to reduce, since the cost can be shared by everyone who buys a car or switches on a light. Clamping down on American steel mills, by contrast, could move production to China, where steel mills can pollute all they want. The upshot would be more greenhouse gases and fewer American jobs.

That's why Bush should return to the Kyoto Accords and join enlightened nations who have pledged to cut their emissions in order to reach global pollution limits. It's also why any free-trade agreements should contain environmental rules.

Business is pushing for a "cap-and-trade" system in America similar to one in Europe. In essence, companies would be allocated a right to pollute at a reduced level. Companies that cheaply can cut their pollution could sell their unused rights to others. American industry believes that a cap-and-trade system could achieve positive results at relatively low cost.

No one knows exactly what global warming will bring or when, but the possibilities truly are frightening: dramatic shifts in food production, new deserts, more frequent and more severe storms, accelerating species extinction and a rise in sea levels and the oceans' salinity.

Denial isn't working: The high court's decision affirmed that. It will take a massive, sustained collaboration involving government, industry, the scientific establishment and consumers to mitigate or forestall global warming's effects. There's no time to waste.